The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
U.S. patent application Ser. No. 10/688,051, filed Oct. 16, 2003, entitled “Policy-based network security management,” by Mark Ammar Rayes et al. (Rayes et al.), describes a policy-based security management controller that can determine what action to take in response to network security attacks, utilizing network alert state, the risk level, and network health state information. In one embodiment, the controller identifies potential intruders using historical alarms or events.
The controller also allows service providers to take action against possible intruders. Action may be required to prevent malicious users from achieving a denial of service (DoS), through techniques such as IP address spoofing, extraneous requests for network addresses under dynamic host control protocol (DHCP) and MAC address spoofing, especially when the network alert level is high. To preserve network integrity and stability, it is important to prevent attackers from inflicting further damage before network performance degrades.
The security controller is the first application that captures possible intruders and takes appropriate action as defined by service providers. However, it may be desirable to take action against a potentially malicious user that is less drastic than completely disabling the user's network access. For example, an unskilled user who is changing a device's IP address too many times during setup time might be inappropriately identified as a malicious user mounting a DoS attack. Denying service to this type of innocent user, because the security controller has inappropriately classified the user as, malicious may induce the user to select another service provider.
On the other hand, the controller is responsible for preventing possible catastrophic network failure, especially during bad network performance. Detailed analysis of suspected user behavior is needed before a service provider can determine whether the suspected user is truly malicious, and such analysis takes time. The controller may decide to disable the user's access, in order to ensure further damage cannot be inflicted, and without waiting for such analysis, despite the fact that this decision may be wrong.
As a result, there is a need for a way to allow service providers to prevent damage to a network without completing blocking network access, while allowing time to apply further diagnostics and analysis to the suspected user's traffic behavior, and without inducing frustration on the part of non-malicious users.